Mesh generation with a standardized headform for CFD simulations of particle aspiration

The aspiration of contaminated airborne particles is a big concern for healthcare workers. Computational Fluid Dynamics (CFD) method has been widely used to simulate breathing airflow and particle aspiration. In CFD simulations of particle aspiration, digital human heads have been integrated into chamber models for mesh generation. Facial dimensions influence the breathing flow pattern and the particle aspiration in the literature; however the existing CFD studies have never included standardized headforms developed from an anthropometric survey of a large American worker population. This study proposed a CFD mesh generation method for particle aspiration simulations based on a medium size standardized headform. The medium headform is one of five National Institute for Occupational Safety and Health (NIOSH) standardized headforms that represent U.S. healthcare workers. To simulate a headform sitting in the middle of a chamber, the volume between the headform and the chamber was meshed. A boundary layer of prism elements covered the headform surface, and a tetrahedral mesh filled the rest of the volume. As an application of the CFD meshes, CFD simulations for particle aspiration were conducted. Velocity fields in the chamber, inhalation flow patterns, and aspiration efficiencies were determined. Further, a grid independency study verified the simulation results and the quality of the CFD meshes.